1. Field of the Invention
The invention relates to a hydraulic shock absorber for absorbing oscillations due to irregular road surface which are input to a wheel of a vehicle such as a motorcycle or the like.
2. Description of Background Art
Conventionally, a structure of a vehicle shock absorber is disclosed wherein damping force is made to have positional dependence (i.e., a characteristic of causing a damping force to change with a contraction position) by providing a plurality of axial holes in a cylinder of a rod type damper and changing the number of the holes according to the sliding position of a piston in the cylinder (for example, refer to JP-A No. 2008-69830).
The above structure allows an air bubble to enter the cylinder via the plurality of holes and, if applied to a front fork in which the cylinder is located above the level of oil in an oil reservoir within a shock absorber body, a hole made in the cylinder causes the oil to come out of the cylinder, which makes it impossible for a damping force to have positional dependence.
Accordingly, an object of the invention is to cause a damping force generated by a damper to have positional dependence even if the damper cylinder is located above the oil level in the oil reservoir within the shock absorber body of a vehicle shock absorber, and also to prevent an air bubble from entering the damper cylinder.